Floristic Diversity and Conservation Status of Guineo-Congolese Species in Southeastern Cameroon: The Case of the Gari-Gombo Communal Forest

The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), Rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.

Surface Reactivity in Tropical Highly Weathered Soils and Implications for Rational Soil Management

Highly weathered soils are distributed in the humid and wet-dry tropics, as well as in the humid subtropics. As a result of strong weathering, these soils are characterized by low activity clays, which develop variable surface charge and related specific properties. Surface reactions regarding base exchange and soil acidification, heavy metal sorption and mobility, and phosphorus sorption and availability of the tropical highly weathered soils are reviewed in this paper.Factors controlling surface reactivity towards cations and anions, including ion exchange and specific adsorption processes, are discussed with consideration on practical implications for rational management of these soils. Organic matter content and pH value are major basic factors that should be controlled through appropriate agricultural practices, in order to optimise favorable effects of colloid surface properties on soil fertility and environmental quality.

Evaluation of Sorghum bicolor in Farmer Field for Resistance to Striga hermonthica

Sorghum bicolor is among main staple crops of Chad but it is commonly attacked by Striga hermonthica. Assessment of sorghum varieties for resistance to this weed was carried out during three cropping seasons （2005-2008）, in controlled conditions; promising entries （those which fulfilled at least 75% of selection criteria） were evaluated in farmer field in 2008-2009 seasons. There were five sites （Bebedjia, Deli, Bekao, Koudoti and Ndaba）. The objective was to evaluate some sorghum entries for S. hermonthica resistance in farmer field. Sorghum test was composed of four entries in Fisher blocks as experimental designs, with five replications. Among different observed variables, there were striga plant count and weight of sorghum grains. One promising entry was selected at Bebedjia and Ndaba （53）, two at Deli and Koudoti （50 and 53）. No entry was selected at Bekao. Promising entries for the whole Southern zone of Chad were composed of 50 and 53. The best entry was 53 because it was promising in all sites except Bekao.

Structure and Reproductive Performances of Sahelian Goats in the Guera Region, in Central Chad

The purpose of the study was to establish the structure of monitored animal farms and determine reproductive parameters of Sahelian goats in the Guera Region, in Central Chad. Data were collected through longitudinal survey in 27 observatory farms during three years using goats identified by numbered ear tags. The herds were composed on average of about 71% of females. The age pyramid covering all years showed a significant number of males aged between 0 - 1 year and perceptible fall thereafter. However, some stability was observed in the class of the 2 - 8 years old among females. The frequencies of accumulated kiddings showed that 44% of births occurred in the rainy season against 28% respectively in the cool dry and hot dry seasons. Obtained reproduction parameters were: a sex ratio of 0.51 in favor of males, a kidding interval of 10.6 months with significant differences (P < 0.05) according to the rank of birth, an age at first kidding of 16.5 months for females born in monitoring and an age of 20.3 months for all first-kidding, giving an apparent fertility rate of 145%, a fecundity rate of 116% and an abortion rate of 2%. The composition and structure of herds have highlighted the importance of females to ensure the reproducibility of goat production systems. The determined reproduction parameters are references for actions to improve goat rearing in this area.

Contribution to Knowledge of Food Formulation during Lean Periods in the Provinces of Wadi-Fira and West-Ennedi (Chad)

The effects of climate change have had a major impact on forage availability in the Sahel and Saharan regions of Chad in recent years. This has led to the migration of farmers in search of long-distance grazing, thus impacting the potential of the animals to produce good quality milk and meat. It is with this in mind that this study was conducted on the knowledge of feeding practices of animals in the provinces of Wadi-Fira and West-Ennedi (Chad) during the lean period. More specifically, it is a question of collecting some information on the plants consumed by the animals and the way in which the breeders formulate the food ration of their herds in times of deficit. It emerges from this investigation that the herds of animals in the province of Wadi-Fira faced with forage deficit and adapted by consuming the leaves, fruits and seeds of certain tropical plants such as Capparis decidua, Ziziphus mauritiana, Balanites aegyptiaca, Acacia tortilis, Boscia senegalensis, Salvadora percica and Tribulis terristris to compensate for food shortages. This same observation was made in the province of West-Ennedi, since this area is desert with annual precipitation of 150 mm. Natural pasture is only available around water points (ouadis and oasis) in a small area with a high number of herds. Thus, the herds also face a drastic lack of grazing during the deficit periods. However, they adapt by consuming the leaves, fruits and seeds of plants such as Bauhinia sp., Boscia senegalenis, Acacia tortilis, Tribulis terristris, Boscia angustifolia, Bicoma tomentosa, Blepharis linarifolia and Aristida funiculata during lean periods to meet their food requirements. The formulation of the feed ration for animals differs from one area to another. It is mainly based on residues from cereals such as millet (Panicum miliaceum) and sorghum (Sorghum bicolor).

Quantifying Forest Loss in the Mbalmayo Forest Reserve (Center Region, Cameroon)

This study was carried out in the forest reserve of Mbalmayo, Center Region of Cameroon, with the aim to analyze the dynamics of land use/land cover (LULC) changes over the past 30 years. The databases used were made up of 3 Landsat satellite images (5TM of 1990, 7ETM+ of 2005 and 8OLI of 2020). The satellite images were processed using ArcGIS and Erdas Imagine software. Ethnobotanical surveys were conducted to investigate the relationships between the local population and the forest reserve. The Mbalmayo forest reserve is consisted of seven main land cover namely: mature secondary forest, young secondary forest, savanna, fallows and crops, built, bare soil and water surface. The dynamics of the forest cover undergoes more significant changes between the years 1990-2005 with losses estimate at 4762 ha compared to the years 2005-2020 (2231 ha), with a marked decrease in the area of dense forests. This regression is much more important in dense forest vegetation. The forest cover lost 6993 ha (26.92%) of its surface, which corresponds to an average rate of deforestation of 233.1 ha/year. The survey revealed the need for NTFPs for the Mbalmayo reserve forest populations. Indeed, all respondents agreed that they use non-timber forest products from the forest, mainly for medication (37%), wood (34%) and food (24%). Therefore, it becomes urgent to redefine a management plan for the Mbalmayo forest reserve which will define how the forest must be managed in order to avoid the loss of large areas of forests disappearing each year under the human action, which exerts pressure on forest species, thus leading to their possible disappearance.

Identification of Microorganisms in Poultry Farms in N’djamena and the Border Areas of Hadjer-Lamis and Chari-Baguirmi Chad

Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real health problems attributable to a lack of monitoring of the vaccination schedule, inadequate compliance with biosecurity measures and poor application of the Ichikawa rule based on the 5 M’s. Objective: The aim of this article is to identify the microorganisms responsible for contamination of poultry farms in the study area. Method: The study was carried out from 28/04/2022 to 31/01/2023 on the basis of 300 samples taken from feed, drinking water, droppings and scrapings from poultry housing surfaces in the 30 farms that served as a framework for our research. Sampling was of the simple random type, and farms were selected on the basis of the farmers’ consent. The data were recorded on pre-established survey forms. Our study was cross-sectional, descriptive and prospective. Bacteria were isolated using the reference method NF EN ISO 6579 for Salmonella spp. and cultured on the specific medium eosin methylene blue (EMB) for Escherichia coli, Pseudomonas and Citrobacter freundii. Results: The following results emerged from this study: Escherichia coli (5.33%), Pseudomonas (1.33%), Citrobacter freundii (12%) and Salmonella paratyphi (21.68%). Conclusion: Of the 300 samples analysed, 121 (40.33%) were contaminated with pathogens. This high level of contamination is a health problem. The study shows that biosecurity is less satisfactory on the farms visited. Nevertheless, farms with a very satisfactory level of biosafety ensure food safety and variety for the population.

玻利维亚亚马孙河流域上贝尼河的汞污染

小规模采金业,特别是一些从本世纪70年代开始蓬勃兴起这种采金业的热带地区(例如亚马孙河流域),由于汞齐法造成的汞污染是一项受到日益关注的环境问题。这项问题的研究工作在巴西早已开展多年,而玻利维亚这方面的资料尚缺。本文论述了亚马孙河流域一条玻利维亚河系中由水、鱼和人头发所测出的汞污染情况。从鱼和食用食肉鱼类的人头发中都发现了高浓度的汞。食用鱼对健康的潜在危险明显存在于采金活动下游的居民,而在矿区本身却不明显。

CRISPR/Cas9-Targeted Knockout of Rice Susceptibility Genes OsDjA2 and OsERF104 Reveals Alternative Sources of Resistance to Pyricularia oryzae

Rice genes OsDjA2 and OsERF104,encoding a chaperone protein and an APETELA2/ethylene-responsive factor,respectively,are strongly induced in a compatible interaction with blast fungus,and also have function in plant susceptibility validated through gene silencing.Here,we reported the CRISPR/Cas9 knockout of OsDjA2 and OsERF104 genes resulting in considerable improvement of blast resistance.A total of 15 OsDjA2(62.5%)and 17 OsERF104(70.8%)T_(0)transformed lines were identified from 24 regenerated plants for each target and used in downstream experiments.Phenotyping of homozygous T1 mutant lines revealed not only a significant decrease in the number of blast lesions but also a reduction in the percentage of diseased leaf area,compared with the infected control plants.Our results supported CRISPR/Cas9-mediated target mutation in rice susceptibility genes as a potential and alternative breeding strategy for building resistance to blast disease.

Determinants of Agroecological Practices Adoption in the Sudano-Sahelian Zone

Under the combined effect of both climatic and anthropogenic factors, agroecosystems and especially arable soils undergo a worrying and fast degradation in the Sudano-Sahelian zone of Western Africa threatening its socio-economic development. Food systems need to be better managed to be more resilient, to increase agricultural production, while conserving natural resources and biodiversity. Agroecological practices alternatively with traditional cultural techniques have been locally experimented to cope with local pedoclimatic constraints such as weak (low) soil fertility and climate change, increasing food demand and economic conditions. Our work aims at by taking stock of agroecological knowledge as well as the determinants of their adoption with small-scale farmers in Eastern Burkina Faso. A survey (48 farmers) was conducted in Sampieri (Kantchari district), and Logit model was used to determine equations for agroecological practices adoption. Results show that traditional production practices for millet-bean cultural systems are gradually being replaced by those of agroecological. In fact, 60.4% of producers have participated in at least one agroecological training session and 60.8% of producers are interested at least in one agroecological topic. The most adopted and practiced techniques were superficial plowing, stone-rows, zai and compost, single or in combination (60% of the producers). Determinants of these practices adoption were the increased crop yields, improved of producers’ incomes, the provision or otherwise of material and human resources and training. Additionally, variables such as training, possession of agricultural equipment were positively correlated to the adoption of agroecological practices while illiteracy impacts negatively and significantly this adoption. Moreover, agroecological practices had a significant effect on grain and straw yields of sorghum, thus confirming producers’ claims about the improvements in production observed following the adoption of these practices.

Morphological and Biometric Diversity of Colletotrichum capsici Isolates, Causal Agent of Cowpea Brown Blotch Disease (Vigna unguiculata (L.) Walp) in the Sudano-Sahelian Zone of Cameroon

Cowpea [Vigna unguiculata (L.) Walp] is an important legume in the midst of about 170 species of its genus because it is an important source of protein and other essential nutrients for humans and animals. Its production faces many constraints such as the cowpea brown blotch disease caused by Colletotrichum capsici which contributes in wet conditions of the field to losses ranging from 42% to 100%. This study was conducted to identify Colletotrichum capsici isolates responsible for cowpea brown blotch disease and to determine their diversity in the Sudano-Sahelian zone of Cameroon. Identification and isolation were made from cowpea organ samples on the Potato Dextrose Agar (PDA) medium and, morphological and biometric characteristics such as: the colony color, the mycelium shape, the abundance of acervules, the presence or absence of saltations, the mycelial growth rate, the conidia length and width were used to assess the diversity. The results obtained indicate that 55 Colletotrichum capsici isolates have been identified in the Sudano-Sahelian zone of Cameroon. Statistical analysis showed that there is a significant difference between isolates. Isolates showed multiple colony colours and were brown coloured as presented by 36.36% of isolates, compact mycelium is found in 56.36% of isolates, 56.36% of isolates have abundant acervulis, and saltations were absent in 45.45% of C. capsici isolates. The mycelial growth rate is between 6.69 mm/d and 12.33 mm/d. The principal component analysis (PCA) made indicated that there are differences between the observed and measured characteristics. The Hierarchical Ascending Classification (HAC) was done and 10 morphotypes of C. capsici in the Sudano-Sahelian zone were identified.

Genetic factors for differentiated thyroid cancer in French Polynesia:new candidate loci

Background:Populations of French Polynesia(FP),where France performed atmospheric tests between 1966 and 1974,experience a high incidence of differentiated thyroid cancer(DTC).However,up to now,no sufficiently large study of DTC genetic factors in this population has been performed to reach definitive conclusion.This research aimed to analyze the genetic factors of DTC risk among the native FP populations.Methods:We analyzed more than 300000 single nucleotide polymorphisms(SNPs)genotyped in 283 DTC cases and 418 matched controls born in FP,most being younger than 15 years old at the time of the first nuclear tests.We analyzed the genetic profile of our cohort to identify population subgroups.We then completed a genome-wide analysis study on the whole population.Results:We identified a specific genetic structure in the FP population reflecting admixture from Asian and European populations.We identified three regions associated with increased DTC risk at 6q24.3,10p12.2,and 17q21.32.The lead SNPs at these loci showed respective p-values of 1.66×10^(−7),2.39×10^(−7),and 7.19×10^(−7) and corresponding odds ratios of 2.02,1.89,and 2.37.Conclusion:Our study results suggest a role of the loci 6q24.3,10p12.2 and 17q21.32 in DTC risk.However,a whole genome sequencing approach would be better suited to characterize these factors than genotyping with microarray chip designed for the Caucasian population.Moreover,the functional impact of these three new loci needs to be further explored and validated.

Infrastructure Finance under the Framework of the Belt and Road Initiative (BRI)

Infrastructure connectivity is one of the cooperation priorities of the Belt and Road Initiative(BRI).The construction and improvement of infrastructure means a large amount of investment as well as lots of risks.This study tries to gauge the funding needs for the countries along the Belt and Road for infrastructure investment to maintain a relatively rapid economic growth.To make it convenient for analysis,this study only projects the appropriate infrastructure investment demand of 65 countries along the Belt and Road that have relatively complete GDP statistics in recent years.And the projection result is the total appropriate infrastructure investment demand is expected to be about US$11.5 trillion between 2017 and 2021.To overcome the challenges and attract more funds to meet the large-scale infrastructure investment demand of the BRI countries,it is critical to improve the infrastructure investment environment in the region.Besides governments’functions of improving investment environment,the role of private investors is of equal importance as market rules and international norms are followed in the process of facilities connectivity construction of the BRI.